Composition for preventing set-offs in printing.



UNITED srArEs PATENT OFFICE.

GEORGE STEELE DUNCAN AND GEORGE HENRY POTTS, OF EDINBURGH, SCOTLAND, ASSIGNORS TO'AMERICAN OFFSET COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

COMPOSITION FOR PREVENTING SET-OFFS IN PRINTING.

' Patented June 19, 1906.

Application filed August 7, 1905- Serial No. 273,138.

sion of an improved pomade or paste for greasing set off rollers running in contact with the machine-cylinder. It is preferable to apply it when the machine is ready to start printing rather than when the machine is running, and it may be most conveniently applied by means of a clean rag saturated with turpentine or naphtha, which is dip ed into thepomade or paste and the rollers tlien well rubbed with it, or it may be applied with the hand.

The pomade or paste is intended to be used in conjunction with one or other of the liquid compositions for preventing set off which are the subject of applications for Letters Patent by both of us, although in some cases it may be preferred to use these liquid compositions alonethat is to say, withoutthe pomade or paste; the subject of our present invention, as will robably be the case if the machine. is one w 'ch registers badly. Although we have not found itdesirable to use the pomade or paste alone, this may be done, and the result from the standpoint of preventing set-off will be better than if neither the pomade or paste nor any of such liquid compositions is used. There is described in the specifica'tion of application Serial No. 259,374 a pomade or paste intended to be similarly used, composed of black or soft soap, olive-oil, and turpentine.

I ject of our present invention has been found to possess advantages over the pomade or The pomade or paste the sub' paste the subject of the said application in that for some classes of work the black or soft soap, even when its alkalinity is counteracted by the addition of lard, causes the parchment or other paper on the set-off cylinder to crack or break too readily. Although the pomade or paste, the subject of our present invention, contains soft soap, these drawbacks are absent.

The constituents of the pomade or paste, the subject of our present invention, are brown Windsor soap, turpentine as ordinarily used by printers, olive-oil,-and soft soap. The best proportions are the following: eight parts, by volume, of turpentine to, one and a alf parts, by volume, of olive-oil four pounds of brown Windsor soap for every quart of turpentine. The brown Windsor soa turpentine, and olive-oil are heated toget er, under stirring, and soft soap gradually added until the consistency of the heated mass is about that of flour-paste, and the color of the product is substantially a pure white. The mass is then allowed to cool and when cool is ready for use.

Having now described our invention, what we claim, and desire to secure byLetters Patent of the United States, is.

1. A composition for preventing set-off GEORGE STEELE DUNCAN.- GEORGE HENRY POTTS.

Witnesses:

MARY MOCREDIE, WALLACE CRANs'roN FAIRWEATHEE. 

